Self powered electronic current regulator - has transistor with Zener diode in base circuit in series with line

摘要

The electronic current regulator is used to compensate automatically for losses in a line carrying a continuous current. A transistor (3) circuit is connected in series with a line via input and output terminals (1, 2). The base is connected to the junction of a series resistor (7, 8) and zener diode (6) circuit. The zener diode provides a regulated voltage. A resistor (5) is connected in series with the emitter circuit and the zener does not conduct until the current rises to generate a voltage greater than the base emitter voltage of the transistor. The emitter resistor fixes the threshold at which conduction commences. A second zener diode (9) between the emitter and junction of the base circuit resistors conducts when the threshold is exceeded. Any excess current flows in this path.